Integrated circuits are what power many of today's consumer electronics, for instance, cellphones, video cameras, portable music players, computers, etc. As customer demand improves integrated circuit performance, faster, more reliable, and higher-density circuits, need to be produced at a lower cost. Packaging goals of the future for these integrated circuits will be met by increasing the density of chips while reducing the number of internal electrical interconnections. Packaging with fewer interconnects can potentially shorten the circuit length, decreases potential failure points, reduce circuit resistance, and reduce inter-line capacitance or cross-talk. Various techniques, such as, flip chip, gall grid array (BGA), chip on board (COB), and multi-chip modules (MCM), have been developed to meet the continued demands for improving integrated circuit system performance.
For even higher density applications, package assemblies including stacked die configurations have been employed. For example, some stacked die configurations employ an upper die that is sufficiently smaller than a lower die, and therefore, allow direct attachment of the two die. But in other instances the upper die is not sufficiently smaller than the lower die and the use of spacers must be employed.
Spacers can be embodied in many forms. For example, spacers may include dummy semiconductor die (e.g.—semiconductor die without electrical circuitry) or adhesive layers containing spacer elements, such as micro-spheres. Unfortunately, many of these applications still suffer from bulky configurations, substrate warpage, electrical shorting, alignment difficulties, delamination, chip floating problems due to low viscosity adhesives, and low unit productivity because each spacer must be attached to each individual die.
Thus, a need still remains for a stacked device integrated circuit package system, which employs a wafer level spacer system that reduces fabrication complexities and provides a low cost alternative to previous methodologies. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.